Organically modified layered silicates (OLS) with high thermal stability are critical for synthesis and processing of polymer silicate nanocomposites (PLSN). In the current study, non-oxidative degradation chemistry alkyl aryl quaternary phosphonium-modified montmorillonites (P-MMT) was examined using TGA combined pyrolysis/GC-MS. The morphology evolution at elevated temperature investigated in-situ high-temperature X-ray diffraction (XRD) Fourier transform infrared spectroscopy (FTIR)....

A new series of linear, asymmetrical diphenylaminofluorene-based chromophores (AFX) with various strong π-electron acceptors were synthesized and evaluated for two-photon absorptivity. These studied to determine a suitable replacement 2-(4-vinyl)pyridine, the π acceptor our previously reported AFX series, which contains photochemically thermo-oxidatively unstable olefinic unit. In addition benzoyl group (AF-370), these include 2-benzothiazolyl (AF-240), 2-benzoxazolyl (AF-390),...

Abstract High density nanoparticle arrays on surfaces have been created using a template‐assisted approach. Templates were produced by evaporating aluminum onto substrates and subsequently anodizing the to produce nanoporous alumina films. The resulting templates narrow distribution of pore sizes tunable from ∼ 25 70 nm. To demonstrate flexibility this approach for producing various substrates, fabricated silicon oxide, silicon, gold surfaces. In all cases, final chemical etching step...

A new approach to two-photon excited photodynamic therapy has been developed. dendritic array of eight donor chromophores capable absorption (TPA) was covalently attached a central porphyrin acceptor. Steady-state fluorescence measurements demonstrated that the transfer excited-state energy with 97% efficiency. Two-photon excitation at 780 nm resulted in dramatic increase relative model compound. Enhanced singlet oxygen luminescence observed from oxygen-saturated solutions target compound...

Three novel two-photon absorbing (TPA) chromophores with 1,3,5-triazine as the π-electron deficient core, dialkylfluorene aromatic bridges, and diphenylamino groups electron-donating end-groups were prepared. Designated AF-450 (2,4,6-tris[7-(diphenylamino)-9,9-didecylfluoren-2-yl]-1,3,5-triazine), AF-455 (2,4,6-tris[9,9-bis(3,7-dimethyloctyl)-7-(diphenylamino)-fluoren-2yl]-1,3,5-triazine), AF-457 (2,4,6-tris[(7-(diphenylamino)-9,9-diprop-2-enylfluoren-2-yl]-1,3,5-triazine), their overall...

Multiwalled carbon nanotubes (MWNTs) (diameter range, 10−20 nm) were functionalized with 4-methoxybenzoic acid and 4-ethoxybenzoic via a Friedel−Crafts reaction in polyphosphoric to afford methoxybenzoyl- ethoxybenzoyl-functionalized MWNTs. As-received MWNT, methoxybenzoyl-functionalized (MeO-MWNT), (EtO-MWNT) dispersed ethylene glycol (EG). Because of the structural similarity, mixture EtO-MWNT (0.4 wt %) EG was homogeneous dispersion, whereas MeO-MWNT pristine MWNT rather heterogeneously...

Abstract A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO 2 ‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation highly polar methylsulfonyl side groups below glass transition temperature ( T g ≈220 °C), polarization these SO ‐PPOs enhanced, and thus dielectric constant high. Consequently, discharge energy density reached up 22 J cm −3 . its high , ‐PPO 25 sample also exhibited a low loss....

We report the synthesis of amorphous, heat-resistant (Tg ranging from 220 to 246 °C) polyimides cross-linked with a novel tris(azobenzeneamine) cross-linker and examine photodirected bending cantilevers composed these materials exposure linearly polarized, 442 nm light. Increasing concentration 5 20 mol % in network not only serves increase Tg modulus but also results considerable photomechanical response observed as an angle 5° 20°. Adjustment orientation electric field light polarization...

Bending the rules: The role of crystallinity in generation photomechanical effects is examined for a series linear azobenzene-functionalized polyimides. less pyromellitic dianhydride (PMDA) that present polyimide crystalline it is, and therefore more cantilever bends when exposed to light (see figure). Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by authors....

Significance Photomechanical effects in polymers are distinguished by the ease with which actinic light can be regulated to contactlessly trigger magnitude and directionality of mechanical adaptivity spatio-temporal control. The materials examined date have not demonstrated power densities or actuation speeds necessary for applications seeking exploit promise wirelessly triggered actuation. Using design, we employ two classes azobenzene-functionalized demonstrate contactless snap-through...

Polar polyimides with added CN dipoles exhibit higher discharged energy density than nonpolar such as Ultem and Kapton.

Abstract Adding colloidal nanoparticles into liquid‐crystal media has become a promising pathway either to enhance or introduce novel properties for improved device performance. Here we designed and synthesized new hybrid silica passivated with mesogenic monolayer on the surface facilitate their organo‐solubility compatibility in host. The resulting were identified by 1 H NMR spectroscopy, TEM, TGA, UV/Vis techniques, doped dual‐frequency cholesteric host appraise both effect of doping...

Abstract This paper reports on the two‐photon absorption (TPA) and related up‐converted emission properties of a novel series chromophores containing ladder‐type oligo‐ p ‐phenylenes with various π ‐conjugation lengths. The design synthesis these are first discussed. An increase in ‐conjugated length ‐phenylene for leads to an TPA cross‐section together increased fluorescence quantum yield. These exhibit high yields because rigid planar structure oligomers. chromophore enhanced yield would...

Utilization of two-photon (TP) excited fluorescence resonance energy transfer (FRET) within a light-harvesting dendrimer has proven to be reliable method for the enhancement effective TP absorption efficiency many FRET acceptor molecules. This approach enabled photosensitization singlet oxygen from porphyrin in both aqueous and organic media using wavelengths more transmissive human body tissue (750−1000 nm). ability utilize near-infrared irradiation induce photochemical reactions is...

Two-photon lithography was used to microfabricate hydrogels (see figure) directly in aqueous solution using non-ionic surfactant as a dispersant for large two-photon absorption cross-section hydrophobic chromophores.

ABSTRACT Three new isomeric diamines containing three, oxy‐linked benzonitriles (3BCN), one of which is asymmetric (meta, para, or m, p), are synthesized in a 3‐step sequence. Polycondensation these and four common dianhydrides (6FDA, OPDA, BTDA, PMDA) N,N ‐dimethylacetamide via poly(amic acid) precursors thermal curing at temperatures up to 300 °C lead three series tough, creasable polyimide (PI) films (tensile moduli = 1.63 − 2.86 GPa). Among PIs, two PMDA‐based PIs possess relatively high...

Azobenzene-functionalized polyimide materials can directly transduce light into mechanical force. Here, we examine the impact of polymer backbone rigidity on photomechanical response in a series linear, azobenzene-functionalized polymers. The was varied by polymerization five dianhydride monomers with newly synthesized diamine (azoBPA-diamine). linear polymers exhibit glass transition temperatures (Tg) ranging from 276 to 307 °C and maintain excellent thermal stability. these characterized...

Two-photon absorption (2PA) spectra (650–1000 nm) of a series model chromophores were measured via newly developed nonlinear spectral technique based on single and powerful femtosecond white-light continuum beam. The experimental results suggested that when either an electron-donor or electron-acceptor was attached to trans-stilbene at para-position, enhancement in molecular two-photon absorptivity observed both cases, particularly the 650–800 nm region. However, push–pull with donor...

Well-aligned rectangular-shaped nanodiamond fibers (NDFs) with a length-to-width ratio of over 1000 were formed on large-scale via self-assembly process by drying acid-treated nanodiamonds uniform size (∼4 nm) from an aqueous solution. Nanodiamond thin films (NDTFs), instead NDFs, have also been prepared the ND dispersion at sufficiently low temperature (< 70 °C)) and/or pH 4). Detailed conditions, including and temperature, for formation NDFs NDTFs process, together structure property...

Abstract A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO 2 ‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation highly polar methylsulfonyl side groups below glass transition temperature ( T g ≈220 °C), polarization these SO ‐PPOs enhanced, and thus dielectric constant high. Consequently, discharge energy density reached up 22 J cm −3 . its high , ‐PPO 25 sample also exhibited a low loss....

The effect of plasmonic enhancement on the two-photon absorption cross section organic chromophores attached to polyelectrolyte-coated gold nanorods was investigated. magnitudes such enhancements were confirmed using single and two photon excitations chromophore molecules bound nanorods. By synthesizing two-, four-, six-, eight-polyelectrolyte layer coated a particular aspect ratio, distance dependence evanescent electromagnetic field molecular observed. Enhancements 40-fold observed for...